Discussion of Growth Process of Micro-arc Oxidation Film on Magnesium Alloys

The growth process of micro-arc oxidation film on magnesium alloys and the influencing factors were discussed.It was indicated that the processbelongs to the submonolayer growth,the film is growing and forming by the end of a cyclic process “film forming breakdown melting sintering reforming……”.The film formed in the early stage is more compact than in the later stage.The loose layer is formed mainly in the later growth stage.The relations between the film-forming voltage,current,electrolyte system and film growth were studied as well.It was found that the higher the voltage,the greater the thickness of film,and the quality and property of the film are better when the current density is 20A/dm2 and the solution is silicate but not aluminate and phosphate.